The invention relates to welding apparatus, and more particularly to submerged-arc welding apparatus. The invention also relates to the manufacture of electric mining shovels, hydraulic mining shovels, dragline mining shovels and related heavy mining machinery.
In submerged-arc welding, flux is deposited along the weld path, and an arc is created between a continuous electrode wire and the metal being welded. The arc melts some of the flux and is submerged in the liquid slag so produced. It is known to provide a circular weld by fixing a submerged-arc welding torch on the end of an arm that rotates about the center of a circle.
Circular welds on heavy mining machinery have traditionally been accomplished by using hand-held semi-automatic welding apparatus. Because of the size and length of the welds, the weld appearance is inconsistent and includes many start and stop locations. The hand-held process requires that the faces and start-stop locations be ground and dressed up. Machining of these locations is difficult due to slag and porosity in the welds.